The present invention relates generally to a container trailer chassis, and more particularly, the invention relates to a chassis which is capable of transporting a standard relatively short container which is heavily loaded.
There are many trailers described in the art suitable for transporting either standard 40 foot containers or 20 foot containers. However, most such trailers are not adapted to easily and economically transport a 20 foot or other relatively short container which is heavily loaded. The Interstate Bridge Laws dictate the maximum weights or loads trucks or the like can carry over bridges on interstate and other public highways. The amount of weight a truck can carry over a bridge is a function of the wheel base to wheels.
The following Federal Bridge Formula is used to calculate the maximum amount of weight a truck can bear.
Formula B: W=500(LN/N-1+12N+36) PA0 W=maximum weight in pounds carried in any group of two or more axles computed to the nearest 500 pounds. PA0 L=distance in feet between the extremes of any group of two or more consecutive axles PA0 N=number of axles in the group under consideration.
Thus, in accordance with the above-identified formula, the longer the trailer the less stress on the bridge. As previously indicated, the two most standard or popular containers are the 20 foot container and the 40 foot container. A 20 foot container weighs approximately 4,000 pounds and can carry a load of 50,000 pounds on a standard 20 foot chassis. However, it is sometimes desirable to use a 20 foot container to carry a load which weighs over 50,000 pounds.
In order to accomplish this and be within the Federal Highway Laws, the chassis must extend beyond the 20 foot container.
There are many chassis on the market which extend beyond the standard 20 foot container. For example, there are prior art chassis which extend 3 feet in front of the container and approximately 4 feet beyond the container. The overall length of this chassis is 27.5 feet. However, the length of this chassis does not increase the overall amount of weight which the truck can bear under the aforementioned Federal Highway Laws. Moreover, when a standard 20 foot container is mounted on a 40 foot chassis, it is difficult to load and unload the container from a loading dock.
Heretofore, attempts to use an extendible chassis with a heavily loaded 20 foot container have been unsuccessful. When a heavily loaded container is mounted on an extendible chassis, the steel beams of the upper chassis gall or tear at the steel beams of the extendible or lower chassis member. This is due to the fact that the bearings used heretofore were not able to carry the extra weight.
Accordingly, a general object of the present invention is to provide a new and improved extendible trailer chassis, which is simple in design and easy to manufacture and moves between a retracted position and an extended position.
A more particular object of the present invention is to provide an extendible chassis having a roller bearing that can withstand a relatively high amount of weight related stress.
These and other objects and features of the present invention will become more apparent from the reading of the following descriptions.